where \(x_{i, \mathrm {CMB}} \equiv \left(R\left(z_{*}\right), \ell _{A}\left(z_{*}\right), \Omega _{b}h^2\right)\)  with \(R=1.7502\) , \(\ell _A=301.471\)  and \(\Omega _bh^2=0.02236\)  [1]}, and their inverse covariance matrix \(C_{\mathrm {CMB}}^{-1}\)  can be given as
\(C_{\mathrm {CMB}}^{-1}=\left(\begin{array}{ccc}94392.3971&-1360.4913&1664517.2916 \\-1360.4913&161.4349& 3671.6180 \\1664517.2916& 3671.6180& 79719182.5162\end{array}\right).\) 
